package com.java.es.an;

import java.lang.reflect.Field;

/**
 * @author jiangli
 * @date 2019/11/21 20:17
 */
public class Demo {

	public static void main(String[] args)throws Exception{
		//通过反射获取类
		Class<?> forName = Class.forName("com.java.es.an.People");
//		Annotation[] annotations = forName.getAnnotations();
//		for (Annotation annotation : annotations) {
//			System.out.println(annotation);
//		}
		//拼接sql
		StringBuilder sb =new StringBuilder();
		sb.append("select ");
		//通过类的成员变量的注解获取数据库表的字段
		Field[] fields = forName.getDeclaredFields();
		for (int i = 0; i < fields.length; i++) {
			SetField setField = fields[i].getAnnotation(SetField.class);
			String property = setField.name();
			sb.append(property);
			if (i == fields.length - 1) {
				sb.append(" from ");
			}else {
				sb.append(" ,");
			}
		}
		//获取表名
		SetTable setTable = forName.getAnnotation(SetTable.class);
		sb.append(setTable.value()).append(";");
		System.out.println(sb.toString());

	}
}
